Distributor seat provided with a pneumatically adjustable port



Nov. 19, 1963 1 DE SAINT MARTIN 3,111,243

DISTRIBUTOR sEAT PROVIDED WITH' A PNEUMATIOALLY ADJUSTABLE PORT Filed May 17, 1960 Fig par mn.

United States Patent O 3,111,243 DISTRIBUTOR SEAT PRQVWED WITH A PNEU- MATICALLY ABIUSTABLE PORT Lucien de Saint Martin, Le Pecq, France, assigner to institut de Recherches de la Siderurgia Francaise, Saint Germain-on-Laye, France, a French institution Filed May 17, 1969, Ser. No. 29,724 Claims priority, application France May 22, 1959 6 Claims. (Cl. 222-193) My invention has for its object a seat provided with an adjustable port for static powder distributors.

Powder distributors operating under pressure, which are in current use, are provided with an outlet port of unvarying cross-section. A needle valve controlled by a jack may, for instance, close said outlet port. In its raised position, said needle valve does not hinder the flow of powder and the rate of the later is adjusted by increasing or reducing the diEerence between the pressure inside the distributor and the pressure inside the transport line. However, the range of rates of liow which it is possible to obtain in this manner is comparatively narrow. On the one hand, it is not possible to increase indefinitely the pressure inside the distributor and, on the other hand, when the inner pressure is equal to the pressure prevailing in the transport line, the powder flows out under the action of its own weight at a rate which is not negligible. In practice, it may be stated that the ratio between the maximum and minimum rates of ow is equal to 5.

Sometimes, there is positioned at the outlet of the powder distributor a diaphragm valve for adjusting the rate of flow of powder. Such a method is objectionable because the outlet port is not circular but elongated for low rates of ow and there is a risk of clogging by the powder; furthermore, the intense abrading action observed prevents application of said method in many cases.

On the other hand, it was not possible hitherto to obtain very small and uniform flows of the powder with the powder distributors operating under pressure of a conventional type, since, if the diameter of the port is too small, say less than 2 mm., this leads to a clogging, whatever may be the size of the powder used, or else, if the port in the seat has a sufficient diameter of at least 2 mm., the powder flows under the action of mere gravity at a rate higher than the desired rate. It is true that it is possible to reduce the average rate of flow of powder by maintaining inside the distributor a pressure lower than that existing in the transport line, but this leads to a flow of powder in the form of pulses, this being wholly comparable to the phenomena accompanying the emptying of a bottle after complete turning upside down of the latter. It |will be readily ascertained that such a pulse-shaped flow is unsuitable whenever a constant concentration is to be obtained.

My invention has for its object to remove said drawbacks and to allow, through a novel arrangement, an adjustment of the rate of flow of powder lWithin a very large range, say as between 1 and 100, while producing a uniform and highly reduced ow, say less than l gr. per second, without any risk of clogging the outlet port.

My invention has consequently provided a pneumatic arrangement for the adjustment of the rate of ow of powder passing out of a static distributor of powder under pressure, said arrangement including an outlet port for the distributor, which port is provided with means connected with a pipe feeding an auxiliary compressed gas, said means being designed so as to project, on the stream of powder passing through said outlet, a stream extending transversely with reference to the direction of said powder stream land formed by the auxiliary gas exerting on said powder stream a constricting action, adjusting means 37,1 l 1,243 Patented Nov. 19, 1963 being inserted in said pipe feeding compressed gas, so as to adjust the penetration of the auxiliary gas stream.

I will now describe an embodiment of my invention, by Way of a mere example and by no means in a limiting sense, reference being made to the accompanying drawings, wherein:

FIG. l is a partial sectional View showing the lower end of a powder distributor provided with a seat having an adjustable port according to my invention.

FIGS. 2 and 3 illustrate in separate axial cross-sectional views the two parts forming the seat with an adjustable port.

FIG. 4 is a curve illustrating the rate of ow of the powder as a function of the pressure of the auxiliary gas, for a pressure inside the static distributor equal to 4 kgs. per sq. cm.

The distributor illustrated in FIG. l includes `a support 1 forming the bottom of a staticv distributor of powder of a known type. The shape of said support is designed in a manner such that it may be engaged by a block of metal 2 which is secured on the support by the threaded nut 3.

As apparent from inspection of FIG. 2, the block 2 is provided with a recess adapted to carry the seat 5 illustrated separately in FIG. 3.

Said seat 5 is provided on its lofwer surface with an annular groove 6 which subdivides said lower surface into two sections, to wit: an outer annulus 7 and an inner circle S, the outer surface of which circle lies by 1A@ mm. to the rear of the outer surface of the peripheral annulus 7.

When said two parts 2 3 are fitted on the static distributor, as illustrated in FIG. l, the groove 6 registers with the terminal port of a channel 9 cut in the block 2. It is thus apparent that, during operation, the auxiliary gas fed from a supply which is not illustrated and which is connected through conduit 14 with the channel 9, is distributed into the annular groove 6 and thence into the gap lll extending between the annulus 8- on the seat and the block 2. The auxiliary gas converges throughout the circumference defined by the groove 6 towards the outlet port 11 extending through the center of the seat and it will be readily understood that a modification of the ow of the auxiliary gas by means of adjustment of valve 16 in conduit i4 acts on the rate of flow of the powder passing out of the distributor through the port 11 and escaping through the outlet channel 12 formed in the block 2.

A numeric example illustrating operation appears in FIG. 4. In said figure, the abscissae designate the pressures of the auxiliary gas acting through the annular groove, while the ordinates show the rate of ow of the powder in kgs. per minute.

The curve drawn in FIG. 4 shows the modifications in the rates of flow of the powder when the pressure of the auxiliary gas varies between O and 6 kgs. per sq. cm. for an unvarying pressure equal to 4 kgs. per sq. cm. inside the distributor. It is apparent that the ow of powder is reduced to zero for a pressure of the auxiliary gas equal to 6 kgs. per sq. cm. In this particular case, the ratio between the maximum rate of flow and the minimum rate is thus theoretically iniinite.

It is an easy matter to associate my improved seat provided with an adjustable port with an automatic adjustment of the powder flow.

Obviously, it is possible to imagine various modifications and detail improvements Within the scope of the accompanying claims and, in particular, it is possible to substitute for the means disclosed equivalent means.

What I claim is:

1. Adjustable discharge arrangement for discharging powdery material from a container comprising, in combination, downwardly directed tubular discharge means communicating at the upper end thereof with a bottom region of the container so that powdery material contained in said container will enter said tubular discharge means -at the upper end thereof, said tubular dicharge means being open at the bottom end for discharge of the powdery material which entered it at its upper end, said tubular discharge means having at said upper end thereof a portion of smaller cross section than the remainder of said tubular discharge means and being formed at the downstream end of said portion with an annular slot open toward the inner surface f said tubular discharge means land extending substantially in a plane normal to the elongation of said tubular discharge means; means for introducing a gaseous medium under pressure into said slot so that the gaseous medium under pressure will pass into said downwardly directed tubular discharge means in radial direction from all sides and substantially normal to the elongation of said downwardly directed discharge means so that said thus introduced gaseous medium will constrict the downward ow of said powdery material to a Variable extent depending upon the pressure of said gaseous medium; and

means for adjusting the pressure of said gaseous medium so Ias to vary the flow retarding effect thereof on said flow of said powdery material.

l2. Adjustable discharge arrangement for discharging powdery material from a container having a bottom portion formed with a recess comprising, in combination, a seat member removably mounted in said recess and being formed with a port extending in substantially vertical downward direction and communicating at the upper end thereof with the bottom region of said container so that powdery material contained in said container may ow downwardly out of the same through said port, said seat member having a bottom face substantially normal to the axis of said port;

Ia block member removably connected to said container and located at least partly in said recess below said seat member and being formed with a bore therethrough axially aligned with said port, said block having `an upper face engaging an outer annular portion of said bottom face of said seat member, one of said faces of one of said members being relieved inwardly of said outer annular portion of said bottom face to provide an annular gap extending outwardly of said port substantially normal to the axis thereof, and said block member being formed with passage means therethrough communicating with said gap for introducing a gaseous medium under pressure into said gap so that said thus introduced gaseous medium will reduce the downward flow of the powdery material to a variable extent depending upon the pressure of said gaseous medium; and

means for adjusting the pressure of the gaseous medium so as to vary the ow retarding effect of said gaseous medium on said flow of powdery material.

3. An arrangement as defined in claim 2 in which said bore has at least in the lower portion thereof a greater cross section than that of said port.

4. An arrangement as defined in claim 3 in which said bore tapers at an upper portion thereof toward said upper face of said block member.

5. Adjustable discharge arrangement comprising, in combination, container means having a bottom portion formed with an outlet port extending in substantially vertical downward direction and communicating at the upper end thereof with said bottom portion of said container means so that powdery material contained in said container means may flow downwardly out of the same through said port, said container means havingaround said port a bottom face substantially normal to the axis of said port; a block member formed with a bore therethrough aligned in axial direction with said port, said block member being connected to said container means with a top face thereof abutting against said bottom face and one of said faces being relieved outwardly of said port to provide an annular gap extending outwardly of said port substantially normal to the axis thereof, `and said block member being formed with passage means therethrough communicating 'with said gap for introducing gaseous medium under pressure into said gap so that the thus introduced gaseous medium under pressure will impinge in radial direction from all sides on the stream of powdery material, flowing downwardly out of said outlet port so as to constrict said ow to a variable extent depending on the pressure of said gaseous medium; and means for adjusting the pressure of the gaseous medium so as to vary the ow retarding effect of the gaseous medium on said ow of powdery material.

6. Adjustable discharge arrangement comprising, in combination, container means having a bottom portion; wall means forming a downwardly extending elongated outlet port communicating at its upper end through said bottom portion of said container means with the interior thereof, said wall means also forming an annular gap extending outwardly of said outlet port and substantially normal thereto; means for introducing gaseous medium under pressure into said gap in such a manner that the thus introduced gaseous medium under pressure will impinge in radial direction from all sides on any material flowing downwardly through said outlet port so as to constrict such flow to a Variable extent depending upon the pressure of said gaseous medium; and means for adjusting the pressure of said gaseous medium so as to vary the ow retarding effect 0f said gaseous medium on said owing material.

References Cited in the le of this patent UNITED STATES PATENTS 2,577,664 Pro Dec. 4, 1951 2,914,916 Gelin et al Dec. 1, 1959 2,946,667 Le Lara et al July 26, 1960 2,957,306 Attinello Oct. 25, 1'960 FOREIGN PATENTS 494,985 Italy June 7, 1954 

1. ADJUSTABLE DISCHARGE ARRANGEMENT FOR DISCHARGING POWDERY MATERIAL FROM A CONTAINER COMPRISING, IN COMBINATION, DOWNWARDLY DIRECTED TUBULAR DISCHARGE MEANS COMMUNICATING AT THE UPPER END THEREOF WITH A BOTTOM REGION OF THE CONTAINER SO THAT POWDERY MATERIAL CONTAINED IN SAID CONTAINER WILL ENTER SAID TUBULAR DISCHARGE MEANS AT THE UPPER END THEREOF, SAID TUBULAR DISCHARGE MEANS BEING OPEN AT THE BOTTOM END FOR DISCHARGE OF THE POWDERY MATERIAL WHICH ENTERED IT AT ITS UPPER END, SAID TUBULAR DISCHARGE MEANS HAVING AT SAID UPPER END THEREOF A PORTION OF SMALLER CROSS SECTION THAN THE REMAINDER OF SAID TUBULAR DISCHARGE MEANS AND BEING FORMED AT THE DOWNSTREAM END OF SAID PORTION WITH AN ANNULAR SLOT OPEN TOWARD THE INNER SURFACE OF SAID TUBULAR DISCHARGE MEANS AND EXTENDING SUBSTANTIALLY IN A PLANE NORMAL TO THE ELONGATION OF SAID TUBULAR DISCHARGE MEANS; MEANS FOR INTRODUCING A GASEOUS MEDIUM UNDER PRESSURE INTO SAID SLOT SO THAT THE GASEOUS MEDIUM UNDER PRESSURE WILL PASS INTO SAID DOWNWARDLY DIRECTED TUBULAR DISCHARGE MEANS IN RADIAL DIRECTION FROM ALL SIDES AND SUBSTANTIALLY NORMAL TO THE ELONGATION OF SAID DOWNWARDLY DIRECTED DISCHARGE MEANS SO THAT SAID THUS INTRODUCED GASEOUS MEDIUM WILL CONSTRICT THE DOWNWARD FLOW OF SAID POWDERY MATERIAL TO A VARIABLE EXTENT DEPENDING UPON THE PRESSURE OF SAID GASEOUS MEDIUM; AND MEANS FOR ADJUSTING THE PRESSURE OF SAID GASEOUS MEDIUM SO AS TO VARY THE FLOW RETARDING EFFECT THEREOF ON SAID FLOW OF SAID POWDERY MATERIAL. 